Most Samsung microwaves have a built-in light that shines while the unit is in use. It shows you what is happening to your food as it cooks and lets you visually check on the progress. Although you can still use a microwave without the light, it's a small convenience that makes a big difference. Over time, your microwave's light bulb will burn out. Although the process may vary by microwave model, changing the light bulb is a quick task once you've removed the bulb cover.
Turn off the Samsung microwave and unplug it from the electrical outlet.
Remove the bulb cover's mounting screws with a screwdriver, then remove the bulb cover from the front of unit.
Unscrew the light bulb from its socket, and screw in a replacement 40-watt bulb.
Place the bulb cover back in its place and screw the mounting screws back into place.